伤寒患者退热1～3周后，临床症状再次出现称为（）
A.再燃
B.复发
C.二重感染
D.再感染
E.重复感染
参考答案：B
155. The teacher was a little angry because the students didn’t _____ their exercise books on time.
A．hand out
B．hand to
C．hand in
D．hand on
正常精液中前列腺液约占()
A．10%
B．20%
C．30%
D．40%
E．50%
